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Biomedical subjects

P Mavrocordatos

Publications and source records attributed to P Mavrocordatos.

8 recordsLinked to original sources
PubMed2006

[Novelties in interventional pain techniques].

The clinical application of new interventional technology begins with its conception, passes through a scientific validation and finally should be accepted as part of current clinical practice. One way of scientifically validating these techniques is analyzing present practice, available resources and patient outcome. The first part of this article describes the stages in the creation of a quality management system (ISO 9001) which we carried out, in order to judiciously realize these novel interventions. In the second part two techniques indicated in low back and leg pain are described. The first is spinal endoscopy, a three dimensional procedure designed to diagnose and treated painful lumbar radiculopathy. The second is intra-discal electro-therapy (IDET), indicated in discogenic pain. Albeit novel, these techniques are of promising nature, and their qualitative analysis, via rigorous certification is, we think, of interest.

Chronic Disease↗
PubMed2006

Minimally invasive procedures for the treatment of failed back surgery syndrome.

Failed back surgery syndrome has become unfortunately a common clinical entity. FBSS does not have one specific treatment because it does not have one specific cause. Some features are shared with chronic low back pain (CLBP) and some pathological processes are specific. Both pathologies are leading causes of disability in the industrialized world and costly medical and surgical treatments are continuously used despite their limited efficacy. Nonetheless, evidence based practice guidelines are systematically developed. In this chapter we cautiously review the vast, complex and at times contradictory literature regarding the treatment of FBSS. Interventional Pain literature suggests that there is moderate evidence (small randomized or non randomized or single group or matched case controlled studies) for medial branch neurotomy and limited evidence (non experimental one or more center studies) for intra-discal treatments in mechanical low back pain. There is moderate evidence for the use of transforaminal epidural steroid injections, lumbar percutaneous adhesiolysis and spinal endoscopy for painful lumbar radiculopathy and spinal cord stimulation and intrathecal pumps mostly after spinal surgery. In reality there is no gold standard for the treatment of FBSS but, these results seem promising.

Adrenal Cortex Hormones↗
PubMed2000

Effects of neck position and head elevation on intracranial pressure in anaesthetized neurosurgical patients: preliminary results.

This study reports the collective effect of the positions of the operating table, head, and neck on intracranial pressure (ICP) of 15 adult patients scheduled for elective intracerebral surgery. Patients were anesthetized with propofol, fentanyl, and maintained with a propofol infusion and fentanyl. Intracranial pressure was recorded following 20 minutes of stabilization after induction at different table positions (neutral, 30 degrees head up, 30 degrees head down) with the patient's neck either 1) straight in the axis of the body, 2) flexed, or 3) extended, and in the five following head positions: a) head straight, b) head angled at 45 degrees to the right, c) head angled at 45 degrees to the left, d) head rotated to the right, or e) head rotated the left. For ethical reasons, only patients with ICP < or = 20 mm Hg were included. Intracranial pressure increased every time the head was in a nonneutral position. The most important and statistically significant increases in ICP were recorded when the table was in a 30 degree Trendelenburg position with the head straight or rotated to the right or left, or every time the head was flexed and rotated to the right or left-whatever the position of the table was. These observations suggest that patients with known compromised cerebral compliance would benefit from monitoring ICP during positioning, if the use of a lumbar drainage is planed to improve venous return, cerebral blood volume, ICP, and overall operating conditions.

Adult↗
PubMed1994

O2 consumption by the fick method. Methodologic factors.

This study aimed to compare O2 consumption (VO2) determination by the gas-exchange (VO2GE) and Fick (VO2F) methods in cardiac surgical patients. A total of 10 mechanically ventilated postoperative patients were studied prospectively. Thermodilution was performed using three randomly applied techniques: room temperature saline injected at end expiration, room temperature saline randomly injected in the respiratory cycle, and iced saline injected at end expiration. The influence of the number of thermodilution determinations was assessed by comparing results from 2 and 10 injections. The variability of VO2F was greater than that of VO2GE. There was no bias between VO2GE and VO2F values using injectate at room temperature. Accuracy and precision were not improved by increasing the number of cardiac output determinations from 2 to 10. A significant bias was observed using ice-cold injectate, VO2F being 18.0 +/- 15.4 ml/min/m2 lower than VO2GE (p = 0.001). Published results when comparing VO2F and VO2GE are discrepant. However, a significant bias was found in all studies using cold injectate, with lower VO2F values. We conclude that iced injectate should not be used to assess VO2 in critically ill patients.

Adult↗
PubMed1993

Effects of infused sodium acetate, sodium lactate, and sodium beta-hydroxybutyrate on energy expenditure and substrate oxidation rates in lean humans.

Infusion of sodium acetate in lean humans results in a decrease in respiratory exchange ratio, which may be advantageous in patients with respiratory failure. However, this potential decrease in respiratory work was observed to be offset by significant thermogenesis. The metabolic effects of sodium acetate, sodium lactate, and sodium beta-hydroxybutyrate, infused at a rate of 20 mumol.kg-1.min-1 for 3 h, was monitored in six healthy human volunteers. Respiratory exchange ratio decreased from 0.85 +/- 0.02 at baseline to 0.75 +/- 0.02, 0.75 +/- 0.02, and 0.80 +/- 0.02, after acetate, lactate, or beta-hydroxybutyrate, respectively (P < 0.05 for each). Acetate produced a larger thermic effect (22.7% of energy infused) than did lactate (16.3%) or beta-hydroxybutyrate (13.6%). Thus, sodium salts of organic acids may potentially decrease the respiratory requirements by decreasing the respiratory exchange ratio. However, this effect is partially offset by the thermic effect of these substrates. The maximal doses and safety of these anions during larger infusion periods remain to be determined.

3-Hydroxybutyric Acid↗
PubMed1993

Prolonged intrathecal fentanyl analgesia via 32-gauge catheters after thoracotomy.

We hypothesized that intrathecal fentanyl infusion would provide excellent analgesia, require lower doses than necessary for the epidural or intravenous route of administration, and reduce the incidence and/or severity of side effects. Accordingly, we studied 12 patients during 48 h after thoracotomy (three pneumonectomies, six lobectomies, and three multiple resections of metastases or pleural surgery). The mean dose of fentanyl infused intrathecally was 0.81 +/- 0.26 microgram.kg-1 x h-1, and plasma fentanyl concentrations ranged between 0.49 +/- 0.19 and 0.72 +/- 0.34 ng/ml. Four patients needed a supplementary bolus of intrathecal fentanyl. Pain scores decreased below 30/100 within 1 h when measured at rest but required 24 h to decrease to the same level during coughing. Pulmonary function tests returned to approximately 50% of preoperative values within 1 h of fentanyl infusion. Mean respiratory rates averaged 19 +/- 4, and no episode of apnea was detected. Pruritus, nausea, and headache occurred, respectively, in four, one, and zero patients. Excessive pressure in the infusion system occurred frequently, limiting fentanyl infusion in two patients. All catheters were removed intact; however, one broke outside of the patient's back. This study demonstrates that intrathecal fentanyl infusion can safely provide rapid and intense analgesia but that current 32-gauge intrathecal catheters are not well suited for prolonged postoperative use.

Adult↗
PubMed1992

A randomized comparison of intravenous versus lumbar and thoracic epidural fentanyl for analgesia after thoracotomy.

Administration of large doses of fentanyl is a popular method to provide postoperative analgesia after thoracotomy. It is however unclear whether epidural lumbar (L) or epidural thoracic (T) administration of fentanyl confers any major advantage over intravenous (iv) infusion. Using a randomized prospective study design, we compared the potential benefits of L, T, and iv fentanyl administration after thoracotomy in 50 patients. Epidural catheters were not injected during surgery. Postoperatively a fentanyl infusion (5 micrograms/ml) was started at 1 microgram.kg-1.h-1 after a bolus of 1 microgram/kg and adjusted to maintain a score < or = 30/100 at rest using a visual analog scale (VAS) for pain. Data were prospectively collected before surgery, at fixed intervals during the 48 h of fentanyl infusions, and the day of discharge. There was no difference between the groups in overall quality of analgesia at rest and after coughing, quantity of fentanyl delivered (L = 1.15 +/- 0.38, T = 1.22 +/- 0.23, iv = 1.27 +/- 0.3 micrograms.kg-1.h-1), incidence of pruritus needing treatment (L = 2, T = 1, iv = 0 patients), need to decrease fentanyl infusion rate because of side effects (L = 2, T = 2, iv = 4 patients), importance of pulmonary infiltrates, or arterial blood gas values. One patient (L group) needed naloxone (0.04 mg iv). Intravenous patients were more frequently nauseated (P = .009) and needed boluses of fentanyl more often (L = 3 +/- 9, iv = 6 +/- 12, T = 4 +/- 8; P = .04).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗